Reasoning by analogy is the norm in the American common-law system. If you were to maliciously cause some sort of dangerous stampede at, say, a sporting event, you would not be able to get off the hook by arguing that you were not in a theater. Once more, I urge people to consider the difference between civil and common law systems. A lot of people seem to assume the standards of one apply to the other.

Then what possibly could? Hegel's ghost?

The improbability of anyone being hurt. If you stand in the middle of a public park and yell 'the sky is falling!!' nobody will take you very seriously, but even if they did and decided that it was necessary to run indoors the probability of a stampede occurring is vanishingly low. But maliciously causing panic in an enclosed space significantly elevates the risk of injury to others, because the more panicked people are, the more irrationally and dangerously they may act, a phenomenon for which we have abundant evidence.